Reactions of ring-slipped iron complexes derived from P(=S)Ph-bridged [1]ferrocenophane: Synthesis of bis(half-sandwich) heterodinuclear complexes

Article abstract of DOI:10.1021/om060020v

P(=S)Ph-bridged [1]ferrocenophane, [Fe{(η⁵-C ₅H₄)₂P(=S)Ph}] (1), reacted under UV-vis photoirradiation with P(OMe)₃, P(OMe)₂Ph, or PMe ₃ to give respective ring-slipped products. The reaction with P(OMe)₃ afforded [Fe{(η⁵-C₅H ₄)(η¹-C₅H₄)P(=S)Ph}{P(OMe) ₃}₂] (2a), while the bulkier P(OMe)₂Ph gave initially the similar complex 2b, but gradual dissociation of the η¹-C₅H₄ moiety took place from the iron center in THF to form [Fe{η⁵-C₅H₄P(=S) Ph(C₅H₄)-KS}{P(OMe)₂Ph}₂] (4b), in which the η⁵-C₅H₄ ring bearing a P=S pendant group adopted an unprecedented η⁵-kS coordination mode and the other C₅H₄ group left the coordination sphere of the iron atom. The reaction with PMe₃ gave directly the corresponding η⁵-kS product 4c in ether, but its P=S group was replaced in THF with the remaining PMe₃ to give [Fe{(η⁵-C ₅H₄)P(=S)Ph(C₅H₄)}(PMe ₃)₃] (3c) with the P(=S)Ph(C₅H₄) group dangling from the η⁵-C₅H₄ ring. When 2a having an η¹-C₅H₄ group was allowed to react with [M(CO)₃(NCMe)₃] (M = Mo, W), the iron-molybdenum and -tungsten heterodinuclear complexes {μ-η⁵: η⁵-(C₅H₄)₂P(=S)Ph-kS}[Fe{P(OMe) ₃}₂]-[M(CO)₃] (M = Mo (5-Mo), W (5-W)) were obtained, in which the two metal fragments were linked with an η⁵-C₅H₄P(=S)Ph(η⁵-C ₅H₄)-kS bridge. In addition, 5-Mo and 5-W were readily converted in acetonitrile to the respective acetonitrile complexes {μ-η⁵:η⁵-(C₅H₄) ₂P(=S)Ph}[Fe(NCMe){P(OMe)₃}₂]-[M(CO) ₃], with the P=S group giving up coordination to the iron center. A variety of these reaction patterns observed were discussed in terms of steric bulkiness and basicity of the phosphorus ligands concerned.

Full text of DOI:10.1021/om060020v

Organometallics 2006, 25, 2301-2307
2301
Reactions of Ring-Slipped Iron Complexes Derived from
P(dS)Ph-Bridged [1]Ferrocenophane: Synthesis of
Bis(half-sandwich) Heterodinuclear Complexes
Yuki Imamura, Kazuyuki Kubo, Tsutomu Mizuta,* and Katsuhiko Miyoshi
Department of Chemistry, Graduate School of Science, Hiroshima UniVersity, 1-3-1 Kagamiyama,
Higashi-Hiroshima 739-8526, Japan
ReceiVed January 7, 2006
P(dS)Ph-bridged [1]ferrocenophane, [Fe{(η5-C5H4)2P(dS)Ph}] (1), reacted under UV-vis photoir-
radiation with P(OMe)3, P(OMe)2Ph, or PMe3 to give respective ring-slipped products. The reaction with
P(OMe)3 afforded [Fe{(η5-C5H4)(η1-C5H4)P(dS)Ph}{P(OMe)3}2] (2a), while the bulkier P(OMe)2Ph gave
initially the similar complex 2b, but gradual dissociation of the η1-C5H4 moiety took place from the iron
center in THF to form [Fe{η5-C5H4P(dS)Ph(C5H4)-κS}{P(OMe)2Ph}2] (4b), in which the η5-C5H4 ring
bearing a PdS pendant group adopted an unprecedented η5-κS coordination mode and the other C5H4
group left the coordination sphere of the iron atom. The reaction with PMe3 gave directly the corresponding
η5-κS product 4c in ether, but its PdS group was replaced in THF with the remaining PMe3 to give
[Fe{(η5-C5H4)P(dS)Ph(C5H4)}(PMe3)3] (3c) with the P(dS)Ph(C5H4) group dangling from the η5-C5H4
ring. When 2a having an η1-C5H4 group was allowed to react with [M(CO)3(NCMe)3] (M ) Mo, W), the
iron-molybdenum and -tungsten heterodinuclear complexes {µ-η5:η5-(C5H4)2P(dS)Ph-κS}[Fe{P(OMe)3}2]-
[M(CO)3] (M ) Mo (5-Mo), W (5-W)) were obtained, in which the two metal fragments were linked
with an η5-C5H4P(dS)Ph(η5-C5H4)-κS bridge. In addition, 5-Mo and 5-W were readily converted in
acetonitrile to the respective acetonitrile complexes {µ-η5:η5-(C5H4)2P(dS)Ph}[Fe(NCMe){P(OMe)3}2]-
[M(CO)3], with the PdS group giving up coordination to the iron center. A variety of these reaction
patterns observed were discussed in terms of steric bulkiness and basicity of the phosphorus ligands
concerned.
O)R, P(dS)R) are considerably limited in number,4,5 primarily
because of the difficulty of preparing a free bridging ligand
(C5H5)2PR due to its instability,6 though some of its derivatives
have been reported as noted below. One notable example is a
thallium salt, Tl2(C5H4)2PPh, which was prepared and used by
Anderson and Lin7 for the preparation of an ansa-zirconocene
dichloride derivative, but the toxicity of Tl limits its utility. Other
examples classified broadly as a phosphorus-linked bis(cyclo-
pentadienyl) ligand are (indenyl)2PPh2-,8 (fluorenyl)2PPh2-,9 and
Introduction
Dinuclear metal complexes in which two metal centers are
held in close proximity have received continuous interest,
because a cooperative interaction with a substrate is expected
for the two metal centers.1 A linked bis(cyclopentadienyl) ligand
(C5H4-ERn-C5H42-) is a useful bridging system for the
dinuclear bis(half-sandwich)-type complexes, in which each
cyclopentadienyl ring holds a respective metal center firmly. A
variety of such dinuclear complexes have been reported, but
most of them are those whose ERn group is CR2 or SiR2, simply
because free ligands are readily available as alkali-metal salts.2,3
On the other hand, the phosphorus analogues (ERn ) PR, P(d
(3) (a) Zhang, Y.; Cervantes-Lee, F.; Pannell, K. H. J. Organomet. Chem.
2001, 634, 102-108. (b) Zhang, Y.; Wang, B.; Xu, S.; Zhou, X.; Sun, J.
Transition Met. Chem. 1999, 24, 722-725. (c) Froehlich, R.; Gimeno, J.;
Gonzalez-Cueva, M.; Lastra, E.; Borge, J.; Garcia-Granda, S. Organome-
tallics 1999, 18, 3008-3015. (d) Amor, F.; de Jesus, E.; Perez, A. I.; Royo,
P.; Vazquez de Miguel, A. Organometallics 1996, 15, 365-369. (e) Sharma,
S.; Cervantes, J.; Mata-Mata, J. L.; Brun, M.-C.; Cervantes-Lee, F.; Pannell,
K. H. Organometallics 1995, 14, 4269-4274. (f) Galakhov, M. V.; Gil,
A.; de Jesus, E.; Royo, P. Organometallics 1995, 14, 3746-3750.
* To whom correspondence should be addressed. Fax: +81-82-424-
0729. E-mail: mizuta@sci.hiroshima-u.ac.jp.
(1) (a) Ceccon, A.; Santi, S.; Orian, L.; Bisello, A. Coord. Chem. ReV.
2004, 248, 683-724. (b) Roesky, H. W.; Haiduc, I.; Hosmane, N. S. Chem.
ReV. 2003, 103, 2579-2595. (c) Albinati, A.; Venanzi, L. M. Coord. Chem.
ReV. 2000, 200-202, 687-715. (d) Wheatley, N.; Kalck, P. Chem. ReV.
1999, 99, 3379-3419. (e) Stephan, D. W. Coord. Chem. ReV. 1989, 95,
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(2) (a) Bitterwolf, T. E.; Gallagher, S.; Rheingold, A. L.; Guzei, A. I.;
Liable-Sands, L. Inorg. Chim. Acta 2005, 358, 449-451. (b) Bitterwolf,
T. E.; Saygh, A.; Haener, J. L.; Fierro, R.; Shade, J. E.; Rheingold, A. L.;
Liable-Sands, L.; Alt, H. G. Inorg. Chim. Acta 2002, 334, 54-58. (c)
Bitterwolf, T. E.; Everly, S. C.; Rheingold, A. L.; Yapp, G. J. Organomet.
Chem. 1997, 531, 1-7. (d) Mkoyan, S. G.; Aliev, Z. G.; Urazovskii, I. F.;
Atovmyan, L. O.; Nifant’ev, I. E.; Butakov, K. A. IzV. Akad. Nauk, Ser.
Khim. 1996, 9, 2269-2272. (e) County, G. R.; Dickson, R. S.; Fallon, G.
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2-
(4) Although bis(ferrocenyl)phosphines also have a C5H4-PR-C5H4
bridge, they are eliminated from the present classification, because the iron
center of the ferrocenyl unit is practically inert to substitution and other
chemical transformations.
(5) (a) Wrackmeyer, B.; Biersack, M.; Brendel, H. D.; Herberhold, M.
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106-109
(6) Mathey, F.; Lampin, J.-P. Tetrahedron 1975, 31, 2685.
(7) (a) Anderson, G. K.; Lin, M. Inorg. Chim. Acta 1988, 142, 7-8. (b)
Anderson, G. K.; Lin, M. Organometallics 1988, 7, 2285-2288. The Tl2-
(C5H4)2PPh they prepared is not a simple salt of Tl+ but is actually a Tl+
complex whose central metal is readily replaced with transition-metal
halides.
10.1021/om060020v CCC: $33.50 © 2006 American Chemical Society
Publication on Web 03/24/2006

2302 Organometallics, Vol. 25, No. 9, 2006
(C5Me4)2PPh2- 10
all of which carry substituents stabilizing the
Imamura et al.
Scheme 1
,
cyclopentadienyl ring electronically and/or sterically.
In the course of our studies on a ring-opening reaction of the
phosphorus-bridged [1]ferrocenophane 1,11 1 was found to give
the ring-slippage product 2 upon photoirradiation.11e Since 2
has an η1-C5H4 moiety available for η5 coordination toward a
second metal fragment, it is considered to be a promising
precursor for the preparation of C5H4-P(dS)R-C5H42--bridged
heterodinuclear complexes. In addition, a PdS group of the P(d
S)R linker can work as a Lewis base, in contrast with the usual
C5H4-ER2-C5H42- systems (ER2 ) CR2, SiR2), for which no
such additional functionality is expected. Here, we report a novel
synthetic route to C5H4-P(dS)R-C5H42--bridged heterodi-
nuclear complexes which have a C5H4-PdS moiety adopting
an unprecedented η5-κS coordination mode.
Results and Discussion
Ring-Slippage Reaction. The P(dS)Ph-bridged [1]ferro-
cenophane 1 suffers severe steric strain,12 because the two C5H4
rings are bridged with a single phosphorus atom. Upon
photoirradiation of 1 in the presence of an excess amount of
phosphite or phosphine, ring slippage of one of the C5H4 rings
takes place to relieve the steric strain (Scheme 1).11e,13 The
structure of the slipped ring depends on the phosphorus ligand
used, as follows. Photolysis in the presence of P(OMe)3 in THF
gives the piano-stool-type iron complex 2a, bearing an η1-C5H4
group and two P(OMe)3 ligands as legs, whereas the corre-
sponding photolysis with PMe3 gives the complex 3c, bearing
three PMe3 legs with the P(dS)PhC5H4 group dangling from
the η5-C5H4 group bound to the metal center.11e To obtain more
information controlling the reaction patterns, a similar reaction
was carried out using P(OMe)2Ph. The cone angles of P(OMe)2Ph,
P(OMe)3, and PMe3 and pKa values of their conjugate acids
are 120, 107, and 118° and 2.6, 2.6, and 8.65, respectively;14,15
P(OMe)2Ph has a basicity similar to that of P(OMe)3 but has a
large cone angle comparable to that of PMe3.
at 205.8 and 204.1 ppm (AB quartet, JPP ) 124 Hz) and at
28.5 ppm. The major signals decreased significantly in intensity
after several hours, while the minor signals increased. This
change was found to be suppressed almost completely in a less
polar solvent such as ether. Thus, the product 2b, giving the
major signals, was isolated successfully by a separate reaction
in ether. The molecular structure of 2b was determined by X-ray
analysis, as shown in Figure 1, where the C5H4-P(dS)Ph-
2-
C5H4 moiety adopts a coordination mode similar to that in
2a reported previously,11e and the iron fragment adopts a piano-
stool geometry with η5-C5H4, η1-C5H4, and two P(OMe)2Ph
groups as ligands. Positions of the two CdC bonds in the η1-
C5H4 ring were readily assigned on the basis of the geometrical
parameters; summations of bond angles around C6 and C7 atoms
are 359.1 and 360.0°, respectively, and the C6-C7 and C9-
C10 bond lengths are 1.378(2) and 1.335(3) Å, respectively,
which are significantly smaller than those of the other three
C-C bonds in the η1-C5H4 ring. These structural characteristics
are consistent with the right-hand structure in Figure 1 and are
similar to those of 2a.11e However, notable structural differences
were found between 2a and 2b in bond angles around the iron
center; the P-Fe-P angle of 101.02(2)° in the P(OMe)2Ph
complex 2b is larger than the corresponding angle of 95.67(7)°
in the P(OMe)3 analogue 2a, whereas the two P-Fe-C7(η1-
C5H4) angles of 88.87(5) and 93.60(5)° in 2b are smaller than
those of 93.3(2) and 95.3(2)° in 2a. These differences indicate
that the two bulkier P(OMe)2Ph ligands in 2b bring about a
severe steric congestion around the iron center to exert a larger
steric demand on the η1-C5H4 ring, which is probably respon-
sible for the spontaneous dissociation of the η1-C5H4 ring from
the iron center in a polar solvent (vide infra). Since 2b dissolved
in CDCl3 also transformed gradually to 4b, which gave the
minor 31P NMR signals in the reaction mixture mentioned above,
we were obliged to measure the 1H NMR spectrum of 2b
contaminated with 4b in CDCl3. However, the signals at 3.09
and 3.22 ppm and at 6.46 and 6.53 ppm were identified as those
due to the CH2 and two olefin protons, respectively, of the η1-
C5H4 ring in 2b, though several signals of 2b overlapped with
those of 4b. These assignments are consistent with the X-ray
structure of the η1-C5H4 ring found in 2b.
After photoirradiation of a THF solution of 1 in the presence
of P(OMe)2Ph, a 31P{1H} NMR spectrum of the reaction mixture
showed major signals at 208.8 and 30.6 ppm and minor signals
(8) (a) Adams, J. J.; Berry, D. E.; Curnow, O. J.; Fern, G. M.; Hamilton,
M. L.; Kitto, H. J.; Pipal, J. R. Aust. J. Chem. 2003, 56, 1153-1160. (b)
Brady, E. D.; Hanusa, T. P.; Pink, M.; Young, V. G. J. Inorg. Chem. 2000,
39, 6028-6037. (c) Paine, R. T.; Light, R. W.; Maier, D. E. Inorg. Chem.
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Organometallics 1999, 18, 6-9. (c) Shin, J. H.; Parkin, G. Inorg. Chem.
Commun. 1999, 2, 428-430.
(11) (a) Mizuta, T.; Imamura, Y.; Miyoshi, K.; Yorimitsu, H.; Oshima,
K. Organometallics 2005, 24, 990-996. (b) Mizuta, T.; Onishi, M.;
Nakazono, T.; Nakazawa, H.; Miyoshi, K. Organometallics 2002, 21, 717-
726. (c) Mizuta, T.; Onishi, M.; Miyoshi, K. Organometallics 2000, 19,
5005-5009. (d) Mizuta, T.; Yamasaki, T.; Nakazawa, H.; Miyoshi, K.
Organometallics 1996, 15, 1093-1100. (e) Mizuta, T.; Imamura, Y.;
Miyoshi, K. J. Am. Chem. Soc. 2003, 125, 2068-2069.
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Willis, A. J. Organometallics 1983, 2, 128-135. (b) Seyferth, D.; Withers,
H. P. J. Organometallics 1982, 1, 1275-1282. (c) Withers, H. P. J.; Seyferth,
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1283-1288. (d) Osborne, A. G.; Whiteley, R. H.; Meads, R. E. J.
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Organometallics 1989, 8, 1-7.

Bis(half-sandwich) Heterodinuclear Complexes
Organometallics, Vol. 25, No. 9, 2006 2303
attached to the η5-C5H4 ring,17 a similar coordination mode is
definitely established in the dinuclear complexes 5-Mo and 5-W,
which be described in the next section (vide infra).
The driving force for the facile dissociation of the η1-C5H4
ring in 2b to form 4b in THF is considered to be the steric
demand exerted by the two P(OMe)2Ph ligands as mentioned
above. In fact, P(OMe)3 in 2a having basicity comparable to,
but a cone angle smaller than, those of P(OMe)2Ph does not
induce such dissociation in THF at room temperature. Because
PMe3 has a cone angle comparable to that of P(OMe)2Ph, the
PMe3 analogue (4c) of 4b is expected to be formed when 1 is
allowed to react with PMe3. 4c was actually obtained directly
by the photolysis of 1 in ether containing excess PMe3, where
immediate precipitation of 4c took place, enabling us to isolate
4c (Scheme 1). However, when the photolysis was carried out
in THF, the free PMe3 ligand present gradually replaced the
coordinating PdS group in 4c to eventually give 3c with the
coordination-free P(dS)Ph(C5H4) group dangling from the η5-
C5H4 ring, as stated earlier (Scheme 1). However, a complex
having an η1-C5H4 ring, that is, the PMe3 analogue (2c) of 2a,
was not observed. It is likely that 2c was once formed also in
this case, but probably it immediately transformed to 4c through
the more facile dissociation of the η1-C5H4 ring in 2c compared
to that in 2a. Since the steric demand of PMe3 is comparable to
that of P(OMe)2Ph, as judged from their similar cone angles, a
much greater donating ability of the two PMe3 ligands is
considered to be one of the probable factors which contribute
additionally to the more facile dissociation in 2c.
Figure 1. ORTEP drawing of 2b with 50% thermal ellipsoids.
Selected bond distances (Å) and angles (deg): Fe-C7 ) 1.9791-
(16), Fe-C1 ) 2.0886(17), Fe-P2 ) 2.1392(5), Fe-P3 ) 2.1530-
(5), S-P1 ) 1.9602(7), P1-C6 ) 1.7627(18), P1-C1 ) 1.8063-
(19), C6-C10 ) 1.466(2), C6-C7 ) 1.378(2), C7-C8 ) 1.527(2),
C8-C9 ) 1.504(3), C9-C10 ) 1.335(3); P2-Fe-P3 ) 101.02-
(2), C7-Fe-P2 ) 88.87(5), C7-Fe-P3 ) 93.60(5), C6-P1-C1
) 98.38(8), P1-C1-Fe ) 115.15(9), C7-C6-P1 ) 117.69(13),
C7-C6-C10 ) 112.31(16), C10-C6-P1 ) 129.10(14), C6-C7-
Fe ) 122.89(12), C8-C7-Fe1 ) 132.78(12), C6-C7-C8 )
104.33(14).
Preparation of Heterodinuclear Complexes. The ring-
slippage product 2a was allowed to react with M(CO)3(NCMe)3
(M ) Mo, W) in THF (eq 1).
4b was isolated after a THF solution of 2b was allowed to
stand for several hours (Scheme 1). 31P{1H} NMR signals of
4b were found to be shifted as a whole only slightly upfield
compared with those of 2b as stated above, suggesting a
structural resemblance of 4b to 2b around the phosphorus atom.
Notable differences between them in the 1H NMR spectra were
discerned with respect to the signals assigned to the slipped
C5H4 ring; the CH2 signals of the η1-C5H4 ring observed in 2b
disappeared completely in 4b, while the total intensity of the
olefinic proton signals around 6.0-6.5 ppm increased from 2H
to 4H. In addition, 13C{1H} NMR signals of the olefinic carbons
appearing at 113.6 and 115.3 ppm in 4b could be assigned to
the anionic C5H4- freed from coordination, judging from their
chemical shifts close to 109.9 and 114.6 ppm of the C5H4- group
in the complex 3c reported previously11e and to the 114.3 and
In the IR spectrum of the resulting product, ν(CO) absorptions
were observed at 1914 and 1806 cm-1 for M ) Mo and at 1907
and 1802 cm-1 for M ) W, indicating the C5H4 group adopting
an η5 coordination mode to the M(CO)3 fragment.18 Structures
of the products 5-Mo and 5-W were determined by X-ray
analysis, as shown in Figures 2 and 3, respectively, where the
Fe fragment and the Mo or W fragment are linked through an
(η5-C5H4)2P(dS)Ph2- bridging ligand. Bitterwolf et al. reported
a similar η1- to η5-C5H4 conversion, in which Ru(CO)2(η5:η1-
C5H4CR2C5H4) reacted with M(CO)3(NCMe)3 (M ) Mo, W),
to give a heterodinuclear complex having a direct Ru-M bond,
i.e., (µ-η5:η5-C5H4CR2C5H4)[Ru(CO)2][M(CO)3].19 In 5-Mo and
5-W, the Fe atom is not bonded to the Mo or W atom, resulting
in a zwitterionic dinuclear structure. The absence of a Fe-M
bond in 5-Mo and 5-W is attributable to the steric bulkiness of
the P(OMe)3 ligands on the Fe fragment, which blocks a close
116.9 ppm signals of Ph3P+-C5H4- 16 In contrast, the chemical
.
-
shift of the ipso carbon of the C5H4 group showed some
difference among the above three compounds: 105.2, 88.7, and
127 ppm, respectively. These spectral data indicate that one of
the C5H4 rings in 4b has completely dissociated from the iron
center, the resulting vacant coordination site having been
occupied probably with a sulfur atom of the PdS group.
Although, to our knowledge, 4b seems to provide the first
example of an η5-κS coordination mode with a PdS pendant
(17) (a) Okuda, J. Dalton Trans. 2003, 12, 2367-2378. (b) Britovsek,
G. J. P.; Gibson, V. C.; Wass, D. F. Angew. Chem., Int. Ed. 1999, 38,
428-447. (c) McKnight, A. L.; Waymouth, R. M. Chem. ReV. 1998, 98,
2587-2598.
(18) (a) Brumas-Soula, B.; Dahan, F.; Poilblanc, R. New J. Chem. 1998,
22, 15-23. (b) Gladysz, J. A.; Williams, G. M.; Tam, W.; Johnson, D. L.;
Parker, D. W.; Selover, J. C. Inorg. Chem. 1979, 18, 553-558. (c) Goldman,
A. S.; Tyler, D. R. J. Am. Chem. Soc. 1986, 108, 89-94.
(19) Bitterwolf, T. E.; Saygh, A. A.; Shade, J. E.; Rheingold, A. L.;
Yap, G. P. A.; Liable-Sands, L. M. Inorg. Chim. Acta 2000, 300-302,
800-809.
(16) (a) Gray, G. A. J. Am. Chem. Soc. 1973, 95, 5092-5094. (b)
Ammon, H. L.; Wheeler, G. L.; Watts, P. H., Jr. J. Am. Chem. Soc. 1973,
95, 6158-6163. (c) Holy, N. L.; Baenziger, N. C.; Flynn, R. M.; Swenson,
D. C. J. Am. Chem. Soc. 1976, 98, 7823-7824.

2304 Organometallics, Vol. 25, No. 9, 2006
Imamura et al.
Figure 4. Geometrical parameters relevant to the PdS pendant
group in dppfS2 (a) and 5-Mo (b).
evidenced by their ν(CO) absorptions being comparable in
wavenumber to those reported for the anionic carbonyl com-
plexes [MCp(CO)3]- (M ) Mo, W).18 The cationic charge is
thus located formally at the iron center, but the highly polarized
P-S bond renders such a simple formalism fruitless. An exact
nature of the P-S bond in R3PdS has been a subject of
controversy.20 On the basis of recent theoretical studies, the bond
is considered as a highly polarized σ-bond with a strong
electrostatic attraction between Pδ+ and Sδ- atoms,21 and thus
the cationic charge is delocalized to some extent to the bridging
P atom in 5-Mo and 5-W.
Figure 2. ORTEP drawing of 5-Mo with 50% thermal ellipsoids.
Selected bond distances (Å) and angles (deg): Mo-C23 ) 1.933-
(3), Mo-C24 ) 1.945(3), Mo-C25 ) 1.945(3), Fe-C1 ) 2.060-
(3), Fe-P3 ) 2.1415(8), Fe-P2 ) 2.1501(9), Fe-S ) 2.3646(8),
S-P1 ) 2.0075(9), P1-C6 ) 1.756(3), P1-C1 ) 1.797(3), P1-
C11 ) 1.801(3); P3-Fe-P2 ) 94.34(3), P3-Fe-S ) 93.66(3),
P2-Fe-S ) 94.29(3), P1-S-Fe ) 83.20(3), C6-P1-C1 )
111.89(13), C6-P1-S ) 113.41(9), C1-P1-S ) 97.42(9).
The coordination of the pendant PdS group to the iron center
forms a four-membered ring comprised of Fe, C(ipso-Cp),
P(bridge), and S atoms in 5-Mo and 5-W. Bond angles within
the ring are summarized in Figure 4 for 5-Mo, where the
corresponding angles for the related ferrocene derivative [Fe-
{C5H4P(S)Ph2}2] (abbreviated as dppfS2) are also given for
comparison.22 In dppfS2, the Fe-C(Cp)-P and C(Cp)-P-S
angles are 126.0 and 113.4°, respectively, and the S atom is
separated by ca. 3.79 Å from the iron center. The corresponding
angles (97.9 and 97.4°) in 5-Mo are significantly reduced as
compared with those of dppfS2 so as to form the Fe-S bond.
As a result, the bridging P atom is displaced from the η5-C5H4
ring plane toward the iron center considerably, the displacement
angle being 26.5°, comparable to those of the highly strained
complex 1, in which the two η5-C5H4 rings of the ferrocene
unit are linked with one P atom.12a Such steric strain is also
inferred from the 13C{1H} NMR spectrum of the ipso carbon
atom of the η5-C5H4 group on the iron atom;23 Mo-5, W-5, 4c,
and 1, all suffering the strain, show the signals at 69.0, 68.4,
71.5, and 28.9 ppm, respectively, while the strain-free 2a, 3c,
and 6-W (vide infra) show the carbon atom at a lower field
(114.4, 96.2, and 92.8 or 94.0 ppm, respectively).24 Such steric
strain built into 5-Mo is probably responsible for its spontaneous
ring-opening reaction taking place in neat MeCN (vide infra).
The PdS bond (2.008(1) Å) in 5-Mo is longer by 0.042 Å than
that of 2a,11e indicating reduced electrostatic interaction between
the Pδ+ and Sδ- atoms in 5-Mo, as is generally observed upon
coordination of R3PdS to a metal fragment.25 The structural
Figure 3. ORTEP drawing of 5-W with 50% thermal ellipsoids.
Selected bond distances (Å) and angles (deg): W-C24 ) 1.947-
(6), W-C25 ) 1.964(6), W-C23 ) 1.970(7), Fe-C1 ) 2.058-
(6), Fe-P3 ) 2.1431(16), Fe-P2 ) 2.1446(17), Fe-S ) 2.3820-
(17), S-P1 ) 1.999(2), P1-C6 ) 1.758(6), P1-C1 ) 1.787(6),
P1-C11 ) 1.793(6); P3-Fe-S ) 93.24(7), P2-Fe-S ) 95.22-
(7), P1-S-Fe ) 83.40(7), C6-P1-C1 ) 109.2(3), C6-P1-S )
114.5(2), C1-P1-S ) 97.78(19).
approach of the two metal centers. The coordination site from
which the η1-C5H4 group has dissociated is now occupied with
a sulfur atom of the PdS group, as seen in Figures 2 and 3.
Cyclopentadienyl ligands bearing a pendant group capable of
coordinating to the metal center have been intensively inves-
tigated in the past decade with reference to the potential utility
of their metal complexes as so-called “constrained geometry”
catalysts for olefin polymerization.17 However, no example
adopting the η5-κS coordination mode is known to date, which
is found for the first time in 5-Mo and 5-W, and probably in
4b and 4c as well. Similar dinuclear complexes are expected to
be formed when 2b is used in place of 2a. 4b and 4c should
also serve as a precursor of them.
(20) (a) Cook, J. B.; Nicholson, B. K.; Smith, D. W. J. Organomet. Chem.
2004, 689, 860-869. (b) Chutia, P.; Kumari, N.; Sharma, M.; Woollins, J.
D.; Slawin, A. M. Z.; Dutta, D. K. Polyhedron 2004, 23, 1657-1661. (c)
Burford, N. Coord. Chem. ReV. 1992, 112, 1-18. (d) Moran, M.; Cuadrado,
I.; Pascual, C.; Masaguer, J. R.; Losada, J. Inorg. Chim. Acta 1987, 132,
257-262.
(21) (a) Chesnut, D. B. J. Phys. Chem. A 2003, 107, 4307-4313. (b)
Dobado, J. A.; Martinez-Garcia, H.; Molina, J. M.; Sundberg, M. R. J.
Am. Chem. Soc. 1998, 120, 8461-8471.
(22) Fang, Z.-G.; Hor, T. S. A.; Wen, Y.-S.; Liu, L.-K.; Mak, T. C. W.
Polyhedron 1995, 14, 2403-2409.
(23) For example: Resendes, R.; Nelson, J. M.; Fischer, A.; Jakle, F.;
Bartole, A.; Lough, A. J.; Manners, I. J. Am. Chem. Soc. 2001, 123, 2116-
2126.
(24) The corresponding signal was not detected for 4b and 6-Mo because
of its inherently low intensity and their low solubility.
(25) (a) Saak, W.; Pohl, S. Z. Naturforsch., B: Chem. Sci. 1988, 43,
813-817. (b) Saak, W.; Haase, D.; Pohl, S. Z. Naturforsch., B: Chem.
Sci. 1988, 43, 289-294.
The Mo or W fragment obviously constitutes the anionic part
of the zwitterionic dinuclear complexes 5-Mo and 5-W, as

Bis(half-sandwich) Heterodinuclear Complexes
Organometallics, Vol. 25, No. 9, 2006 2305
NMR spectra were recorded on a JEOL LA-300 spectrometer.
1H and 13C NMR chemical shifts were reported relative to Me4Si
and were determined by reference to the residual solvent peaks.
31P NMR chemical shifts were reported relative to H3PO4 (85%)
used as an external reference. Elemental analyses were performed
with a Perkin-Elmer 2400CHN elemental analyzer, but satisfactory
results could not be obtained for 4b, 5-Mo, 6-Mo, and 6-W.
characteristics of 5-W are naturally similar to those of 5-Mo,
in particular with respect to the Fe-C(Cp)-P-S four-membered
ring.
The pendant PdS group of 5-Mo and 5-W was found to
dissociate spontaneously from the iron center when they were
dissolved in MeCN. The resulting vacant coordination site was
occupied with MeCN to form 6-Mo and 6-W (eq 2).
Photolysis was carried out with Pyrex-glass-filtered emission
from a 400 W mercury arc lamp (Riko-Kagaku Sangyo UVL-400P).
The emission lines used (nm) and their relative intensities (in
parentheses) are as follows: 577.0 (69), 546.1 (82), 435.8 (69),
404.7 (42), 365.0 (100), 334.1 (7), 312.6 (38), and 302.2 (9).
[Fe{(η5-C5H4)(η1-C5H4)P(dS)Ph}{P(OMe)2Ph}2] (2b). 112 (94
mg, 0.29 mmol), ether (20 mL), and P(OMe)2Ph (0.45 mL, 2.84
mmol) were added to a Pyrex Schlenk tube, and the solution was
irradiated with a 400 W mercury arc lamp at 0 °C for 30 min. The
yellow precipitate that formed was separated by decantation and
washed with hexane. The residue was dried in vacuo to give 2b as
In the 31P{1H} NMR spectrum, signals of 6-Mo appeared at
slightly higher fields than those of 5-Mo. The 1H NMR signals
at 2.38 ppm and the 13C{1H} signals at 6.7 and 135.0 ppm
observed in 6-Mo were assigned to the MeCN ligand coordinat-
ing to the iron center, as judged from the corresponding chemical
1
a yellow powder (154 mg, 80%). H NMR (300.4 MHz, CDCl3):
δ 3.09 (d, JHH ) 24.3 Hz, 1H, CH2), 3.22 (d, JHH ) 24.3 Hz, 1H,
CH2), 3.18 (m, 3H, OMe), 3.45 (m, 3H, OMe), 3.55 (m, 6H, OMe),
3.78 (br, 1H, η5-C5H4), 4.09(br, 1H, η5-C5H4), 5.72 (br, 1H, η5-
C5H4), 6.46 (m, 1H, η1-C5H4), 6.53 (m, 1H, η1-C5H4). Other signals
overlapped with those of 4b. 31P{1H} NMR (121.5 MHz, in
CDCl3): δ 32.5 (s, P(S)Ph), 209.5 (s, P(OMe)2Ph). Anal. Calcd
for C32H35FeO4P3S: C, 57.84; H, 5.31. Found: C, 57.85; H, 5.26.
1
shifts, 2.39 ppm in the H NMR spectrum and 4.29 and 135.7
ppm in the 13C{1H} NMR spectrum of the related [FeCp-
1
{P(OMe)3}2(NCMe)]+.26 Other signals in the H and 13C{1H}
NMR spectra of 5-Mo and 6-Mo indicate that the two P(OMe)3
groups on Fe and the three CO groups on Mo stay almost intact
in the present ring-opening reaction in eq 2. Similar spectral
changes were observed between 5-W and 6-W.
[Fe{η5-C5H4P(dS)Ph(C5H4)-κS}{P(OMe)2Ph}2] (4b). A solu-
tion of 2b (26 mg, 0.04 mmol) in THF (8 mL) was stirred for several
hours. After almost complete conversion of 2b to 4b was confirmed
by monitoring the 31P{1H} NMR signals, the solution was reduced
in volume to 1 mL, and then the product was precipitated by
addition of hexane (10 mL). The product was separated by
decantation and washed with hexane. The residue was dried in
A driving force for the facile substitution of the PdS group
with MeCN in 5-Mo and 5-W is probably the strain built into
the four-membered ring shown in Figure 4. Ph3PdS is known
to possess a strong donation ability comparable to that of PPh3,
MeCN, CO, or C2H4.20d In addition, several examples of the
reversed substitution have been reported; that is, MeCN
coordinating to a metal fragment is readily replaced with Ph3Pd
S, indicative of the latter having a stronger coordination ability
than MeCN.27 Thus, the spontaneous substitution with MeCN
observed in 5-Mo and 5-W is attributable to the aforementioned
severe ring strain, which is relieved upon the substitution. In
other words, the dissociation of the η1-C5H4 ring and the
subsequent formation of the unstable four-membered ring in
Scheme 1 or eq 1 must be substantiated by the stabilization
gained by the accompanying transformation of the nonaromatic
η1-C5H4 ring to the more stable aromatic C5H4 ring. The η5
coordination of the latter C5H4 ring to the M(CO)3 fragment
also adds to the stabilization of 5-Mo or 5-W in eq 1. The Fe-S
bond is maintained in 5-Mo, 5-W, 4b, and 4c unless a competing
ligand such as phosphine or MeCN is present.
1
vacuo to give yellow 4b in almost quantitative yield. H NMR
(300.4 MHz, CDCl3): δ 3.39 (d, JPH ) 10.1 Hz, 3H, OMe), 3.40
(d, JPH ) 10.1 Hz, 3H, OMe), 3.51 (d, JPH ) 10.1 Hz, 3H, OMe),
3.58 (d, JPH ) 10.3 Hz, 3H, OMe), 3.58 (br, 1H, η5-C5H4), 3.92
(br, 1H, η5-C5H4), 4.15 (br, 1H, η5-C5H4), 4.77 (br, 1H, η5-C5H4),
6.12 (m, 2H, C5H4-), 6.25 (m, 2H, C5H4-), 7.29 (m, 2H, Ph), 7.37-
7.63 (m, 9H, Ph), 7.81 (m, 2H, Ph), 7.94 (m, 2H, Ph). 13C{1H}
NMR (75.45 MHz, CDCl3): δ 53.0 (d, JPC ) 6 Hz, OMe), 53.1
(d, JPC ) 9 Hz, OMe), 53.3 (d, JPC ) 8 Hz, OMe), 53.7 (d, JPC
)
6 Hz, OMe), 79.4 (d, JPC ) 9 Hz, η5-C5H4), 81.4 (m, 2C, η5-C5H4),
85.0 (d, JPC ) 9 Hz, η5-C5H4), 105.2 (d, JPC ) 97 Hz, ipso-C5H4-),
113.6 (d, JPC ) 19 Hz, C5H4-), 115.3 (d, JPC ) 18 Hz, C5H4-),
127.9 (d, JPC ) 13 Hz, 2C, Ph), 128.0 (d, JPC ) 14 Hz, Ph), 129.2
(d, JPC ) 10 Hz, Ph), 129.7 (s, Ph), 130.2 (d, JPC ) 9 Hz, Ph),
130.2 (s, Ph), 131.5 (d, JPC ) 3 Hz, Ph), 131.8 (d, JPC ) 11 Hz,
Ph), 139.3 (d, JPC ) 97 Hz, ipso-Ph), 140.2 (d, JPC ) 96 Hz, ipso-
Ph). 31P{1H} NMR (121.5 MHz, in CDCl3): δ 31.2 (s, P(S)Ph),
205.0 (d, JPP ) 124 Hz, P(OMe)2Ph), 206.9 (d, JPP ) 125 Hz,
P(OMe)2Ph).
Experimental Section
General Remarks. All reactions were carried out under an
atmosphere of dry nitrogen using Schlenk tube techniques. All
solvents were dried and distilled from sodium (hexane), sodium/
benzophenone (ether and THF), or P2O5 (acetonitrile). These
purified solvents were stored under an N2 atmosphere. P(OMe)2-
Ph28 and [M(CO)3(NCMe)3] (M ) Mo, W)29 were prepared
according to previously described methods. Other reagents were
used as received.
[Fe{η5-C5H4P(dS)Ph(C5H4)-κS}(PMe3)2] (4c). 1 (117 mg, 0.36
mmol) and an ether solution of PMe3 (0.212 mol/L, 17 mL, 3.60
mmol) were added to a Pyrex Schlenk tube, and the solution was
irradiated with a 400 W mercury arc lamp at 0 °C for 20 min. The
pale green precipitate that formed was separated by decantation
and washed with ether. The residue was dried in vacuo to give 4c
1
as a pale green powder (160 mg, 93%). H NMR (300.4 MHz,
CDCl3): δ 1.39 (d, JPH ) 8 Hz, 9H, PMe3), 1.61 (d, JPH ) 8 Hz,
9H, PMe3), 3.49 (br, 1H, η5-C5H4), 3.80 (br, 1H, η5-C5H4), 4.27
(br, 1H, η5-C5H4), 5.01 (br, 1H, η5-C5H4), 6.29 (m, 4H, C5H4-),
7.51-7.65 (m, 3H, Ph), 8.05 (m, 2H, Ph). 13C{1H} NMR (75.45
MHz, CDCl3): δ 20.9 (dd, JPC ) 22 Hz, JPC ) 3 Hz, PMe3), 21.2
(dd, JPC ) 22 Hz, JPC ) 3 Hz, PMe3), 71.5 (d, JPC ) 86 Hz, ipso-
η5-C5H4), 76.0 (d, JPC ) 9 Hz, η5-C5H4), 77.3 (d, JPC ) 6 Hz,
η5-C5H4), 77.5 (d, JPC ) 5 Hz, η5-C5H4), 80.0 (d, JPC ) 9 Hz,
(26) Schumann, H.; Eguren, L.; Ziller, J. W. J. Organomet. Chem. 1991,
408, 361-380.
(27) Baker, P. K.; Ridyard, S. D. Polyhedron 1993, 12, 915-919.
(28) Collins, D. J.; Drygala, P. F.; Swan, J. M. Aust. J. Chem. 1983, 36,
2095-2110.
(29) (a) Gibson, D. H.; Owens, K.; Mandal, S. K.; Sattich, W. E.; Franco,
J. O. Organometallics 1989, 8, 498-505. (b) Edelmann, F.; Behrens, P.;
Behrens, S.; Behrens, U. J. Organomet. Chem. 1986, 310, 333-355.

2306 Organometallics, Vol. 25, No. 9, 2006
Imamura et al.
Table 1. Crystallographic Data
2a
5-Mo
5-W
formula
cryst color
cryst syst
space group
a (Å)
C32H35FeO4P3S
orange
C25H31FeMoO9P3S
red
C25H31FeO9P3SW
red
orthorhombic
P212121 (No. 19)
9.7430(1)
13.2490(1)
23.1550(2)
90
90
90
monoclinic
P21/n (No. 14)
13.6210(2)
16.9900(3)
14.0890(2)
90
107.170(1)
90
3115.18(8)
4
monoclinic
P21/c (No. 14)
9.7390(1)
21.0770(2)
14.9500(1)
90
90.583(1)
90
3068.61(5)
4
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
2988.96(5)
4
Z
temp (K)
µ(Mo KR) (mm-1
no. of rflns
measd
200
0.741
200
1.154
200
4.610
)
7068
6410
511
0.0390
0.0815
6857
6816
368
0.0388
0.0988
6824
6778
368
0.0397
obsd (I > 2σ(I), 2θ < 55°)
no. of variables
R1
wR2 (I > 2σ(I))a
Flack param
0.1046
0.370 (8)
2.85 (0.779 Å from W)
0.0730/13.6135
largest diff peak(e/Å3)
a/b
0.33 (0.879 Å from P1)
0.0361/2.6791
1.95 (1.420 Å from P1)
0.0459/6.6913
2
2
2
2
2
2
a wR2 ) {∑[w(Fo - Fc )2]/∑[w(Fo )2]}1/2; w ) 1/[σ2(Fo ) + (ap)2 + bp]; p ) (Fo + 2Fc )/3.
η5-C5H4), 96.5 (d, JPC ) 105 Hz, ipso-C5H4-), 113.2 (d, JPC ) 19
Hz, C5H4-), 114.6 (d, JPC ) 17 Hz, C5H4-), 128.1 (d, JPC ) 12
Hz, Ph), 131.4 (d, JPC ) 11 Hz, Ph), 131.7 (d, JPC ) 2 Hz, Ph).
31P{1H} NMR (121.5 MHz, in CDCl3): δ 25.0 (d, JPP ) 69 Hz,
PMe3), 26.0 (d, JPP ) 69 Hz, PMe3), 34.6 (s, P(S)Ph). Anal. Calcd
for C32H35FeO4P3S: C, 55.48; H, 6.56. Found: C, 55.52; H, 6.52.
{µ-η5:η5-(C5H4)2P(dS)Ph-κS}[Fe{P(OMe)3}2][Mo(CO)3] (5-
Mo). 2a11e (115 mg, 0.20 mmol), Mo(CO)3(NCMe)3 (61 mg, 0.20
mmol), and THF (15 mL) were added to a Pyrex Schlenk tube,
and the solution was stirred for 3 h. After the solvent and volatile
species were removed under reduced pressure, the residue was
recrystallized from THF/hexane and washed with hexane. The
product was dried in vacuo to give 5-Mo as a brown powder (139
JPC ) 12 Hz, Ph), 133.6 (s, Ph), 220.9 (s, JCW ) 198 Hz, CO).
31P{1H} NMR (121.5 MHz, in CDCl3): δ 37.4 (s, P(S)Ph), 178.2
(s, P(OMe)3). Anal. Calcd for C25H31FeO9P3SW: C, 35.74; H, 3.72.
Found: C, 35.48; H, 3.69.
{µ-η5:η5-(C5H4)2P(dS)Ph}[Fe(NCMe){P(OMe)3}2][Mo-
(CO)3] (6-Mo). 5-Mo (30 mg, 0.04 mmol) was dissolved in
acetonitrile (3 mL). After the mixture was stirred for several hours,
the solvent was removed under reduced pressure. The residue was
recrystallized from THF/hexane and then washed with hexane. The
product was dried in vacuo to give 6-Mo quantitatively as a yellow
1
powder. H NMR (300.4 MHz, CDCl3): δ 2.38 (s, 3H, CH3CN)
3.46 (br, 1H, C5H4), 3.56 (t, JPH ) 5.5 Hz, 9H, OMe), 3.76 (t, JPH
) 5.3 Hz, 9H, OMe), 4.56 (br, 1H, C5H4), 4.95 (br, 1H, C5H4),
5.23 (br, 2H, C5H4), 5.34 (br, 1H, C5H4), 5.62 (br, 1H, C5H4), 6.05
(br, 1H, C5H4), 7.50 (m, 3H, Ph), 8.25 (m, 2H, Ph). 13C{1H} NMR
(75.45 MHz, CDCl3): δ 6.7 (s, CH3CN), 52.8 (m, OMe), 53.3 (m,
OMe), 69.9 (d, JPC ) 11 Hz, C5H4), 79.7 (d, JPC ) 10 Hz, C5H4),
85.7 (d, JPC ) 12 Hz, 2C, C5H4), 85.9 (d, JPC ) 10 Hz, 2C, C5H4),
88.1 (d, JPC ) 11 Hz, C5H4), 90.3 (d, JPC ) 12 Hz, C5H4), 93.6 (d,
1
mg, 92%). H NMR (300.4 MHz, CDCl3): δ 3.57 (t, JPH ) 5.1
Hz, 9H, OMe), 3.75 (t, JPH ) 5.1 Hz, 9H, OMe), 3.96 (br, 1H,
C5H4), 4.33 (br, 1H, C5H4), 4.76 (br, 1H, C5H4), 5.15 (br, 1H, C5H4),
5.31 (br, 2H, C5H4), 5.36 (br, 2H, C5H4), 7.55-7.72 (m, 3H, Ph),
8.07 (m, 2H, Ph). 13C{1H} NMR (75.45 MHz, CDCl3): δ 52.6 (s,
OMe), 53.0 (s, OMe), 69.0 (d, JPC ) 89 Hz, ipso-C5H4), 79.9 (d,
JPC ) 17 Hz, C5H4), 80.2 (s, C5H4), 80.7 (d, JPC ) 14 Hz, C5H4),
82.9 (d, JPC ) 96 Hz, ipso-C5H4), 84.2 (d, JPC ) 9 Hz, C5H4), 89.8
(d, JPC ) 13 Hz, C5H4), 90.7 (d, JPC ) 13 Hz, C5H4), 93.4 (d, JPC
) 15 Hz, C5H4), 94.4 (d, JPC ) 16 Hz, C5H4), 126.8 (d, JPC ) 87
Hz, ipso-Ph), 128.5 (d, JPC ) 13 Hz, Ph), 131.3 (d, JPC ) 12 Hz,
Ph), 133.3 (s, Ph), 230.7 (s, CO). 31P{1H} NMR (121.5 MHz, in
CDCl3): δ 38.1 (s, P(S)Ph), 178.4 (s, P(OMe)3).
JPC ) 15 Hz, C5H4), 94.3 (d, JPC ) 13 Hz, C5H4), 127.9 (d, JPC
)
12 Hz, Ph), 131.3 (s, Ph), 132.4 (d, JPC ) 11 Hz, Ph), 135.0 (s,
CH3CN), 232.8 (s, CO).31P{1H} NMR (121.5 MHz, in CDCl3): δ
30.9 (s, P(S)Ph), 176.6 (s, P(OMe)3).
{µ-η5:η5-(C5H4)2P(dS)Ph}[Fe(NCMe){P(OMe)3}2]-
[W(CO)3] (6-W). The preparation of 6-W was carried out in a
manner similar to that described above for 6-Mo, using 5-W (25
1
{µ-η5:η5-(C5H4)2P(dS)Ph-κS}[Fe{P(OMe)3}2][W(CO)3] (5-
W). 2a (118 mg, 0.210 mmol), W(CO)3(NCMe)3 (75 mg, 0.19
mmol), and THF (15 mL) were added to a Pyrex Schlenk tube,
and the solution was stirred for 3 h. After the solvent and volatile
species were removed under reduced pressure, the residue was
washed with ether and dried in vacuo to give 5-W as a brown
powder (117 mg, 73%). 1H NMR (300.4 MHz, CDCl3): δ 3.57 (t,
JPH ) 5.3 Hz, 9H, OMe), 3.75 (t, JPH ) 5.3 Hz, 9H, OMe), 3.97
(br, 1H, C5H4), 4.32 (br, 1H, C5H4), 4.77 (br, 1H, C5H4), 5.09 (br,
1H, C5H4), 5.32 (m, 4H, C5H4), 7.55-7.72 (m, 3H, Ph), 8.06 (m,
2H, Ph). 13C{1H} NMR (75.45 MHz, CDCl3): δ 52.8 (s, OMe),
53.2 (s, OMe), 68.4 (d, JPC ) 90 Hz, ipso-C5H4), 80.0 (d, JPC ) 16
Hz, C5H4), 80.3 (d, JPC ) 10 Hz, C5H4), 81.1 (d, JPC ) 14 Hz,
C5H4), 81.3 (d, JPC ) 96 Hz, ipso-C5H4), 84.2 (d, JPC ) 10 Hz,
C5H4), 87.6 (d, JPC ) 12 Hz, C5H4), 88.4 (d, JPC ) 12 Hz, C5H4),
90.4 (d, JPC ) 14 Hz, C5H4), 91.4 (d, JPC ) 15 Hz, C5H4), 126.4
(d, JPC ) 88 Hz, ipso-Ph), 128.7 (d, JPC ) 14 Hz, Ph), 131.5 (d,
mg 0.03 mmol). H NMR (300.4 MHz, CDCl3): δ 2.39 (s, 3H,
CH3CN), 3.48 (br, 1H, C5H4), 3.53 (t, JPH ) 5.3 Hz, 9H, OMe),
3.76 (t, JPH ) 5.3 Hz, 9H, OMe), 4.55 (br, 1H, C5H4), 4.93 (br,
1H, C5H4), 5.18 (br, 2H, C5H4), 5.30 (br, 1H, C5H4), 5.53 (m, 1H,
C5H4), 5.92 (br, 1H, C5H4), 7.51 (m, 3H, Ph), 8.23 (m, 2H, Ph).
13C{1H} NMR (75.45 MHz, CDCl3): δ 6.6 (s, CH3CN), 52.9 (s,
OMe), 53.4 (s, OMe), 70.1 (d, JPC ) 9 Hz, C5H4), 79.7 (d, JPC
)
10 Hz, C5H4), 85.9 (d, JPC ) 11 Hz, 2C, C5H4), 86.4 (d, JPC ) 11
Hz, C5H4), 88.1 (d, JPC ) 12 Hz, C5H4), 90.9 (d, JPC ) 14 Hz,
C5H4), 91.6 (d, JPC ) 12 Hz, C5H4), 92.8 (d, JPC ) 91 Hz, ipso-
C5H4), 94.0 (d, JPC ) 104 Hz, ipso-C5H4), 128.0 (d, JPC ) 12 Hz,
Ph), 131.4 (d, JPC ) 2 Hz, Ph), 132.5 (d, JPC ) 11 Hz, Ph), 132.7
(d, JPC ) 88 Hz, ipso-Ph), 135.2 (s, CH3CN), 223.3 (s, JCW ) 199
Hz, CO). 31P{1H} NMR (121.5 MHz, in CDCl3): δ 30.6 (s, P(S)-
Ph), 175.9 (s, P(OMe)3).
X-ray Crystallography. Suitable crystals of 2b, 5-Mo, and 5-W
were mounted separately on a glass fiber. All measurements were

Bis(half-sandwich) Heterodinuclear Complexes
Organometallics, Vol. 25, No. 9, 2006 2307
made on a Mac Science DIP2030 imaging plate area detector. The
data were collected to a maximum 2θ value of 55.8°. Cell
parameters and intensities for the reflections were estimated using
the program packages of HKL.30 The structures were solved by
direct methods and expanded using Fourier techniques. Non-
hydrogen atoms were refined anisotropically. Hydrogen atoms were
located at ideal positions. All calculations were performed using a
SHELXL-97 crystallographic software package.31 Details of the data
collection and refinement are given in Table 1, and bond distances
and angles, atomic coordinates, and anisotropic thermal parameters
are given as Supporting Information.
Acknowledgment. This work was supported by Grants-in-
Aid for Scientific Research (Nos. 15350035, 16033245, 17036045,
and 17550061) from the Ministry of Education, Culture, Sports,
Science, and Technology of Japan.
(30) Otwinowski, Z.; Minor, W. In Processing of X-ray Diffraction Data
Collected in Oscillation Mode. Methods in Enzymology; Carter, C. W., Jr.,
Sweet, R. M., Eds.; Academic Press: New York, 1997; Vol. 276
(Macromolecular Crystallography, part A), pp 307-326,
(31) Sheldrick, G. M. SHELX-97: Programs for Crystal Structure
Analysis; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
Supporting Information Available: Full crystallographic data
given in as CIF files. This material is available free of charge via
the Internet at http://pubs.acs.org.
OM060020V